biodiversity

Question 1

what is interspecific variation

Answer 1

variation between organisms of different species

Question 2

what is intraspecific variation

Answer 2

variation between organisms of the same species. the individuals are not identical even if they belong to the same specifies

Question 3

how do we ensure individuals chosen are representive of the whole population and not biased

Answer 3

carry out a random sample: divide the area into grids, use a random number generator to obtain a series of coordinates, take samples at the intersection of each pair of coordinates.

Question 4

how do we ensure chance wont effect the study

Answer 4

use a large sample size

Question 5

causes of variation within a species

Answer 5

gene mutations- changes in the base sequence of DNA, production of different enzymes
crossing over- during meiosis the exchange of alleles of the same genes result in new combinations
independent segregation of chromosomes-during the first meiotic division.

Question 6

what factors are controlled entirely by genetic factors

Answer 6

blood group

Question 7

characteristics are mainly influenced by genetic factors are

Answer 7

controlled by one or two genes
expressed as distinct phenotypes with no intermediates e.g tongue roller
represented as distinct groups on bar chart

Question 8

what are environmental factors that effect variation

Answer 8

light, water and nutrient availability affect plants
diet and temperature effect animals

Question 9

characteristics which are significantly influenced by the environment are ?

Answer 9

controlled by many genes
have no separate categories or types but have a range of intermediates
produce a curve of normal distribution

Question 10

what is standard deviation

Answer 10

measure of the spread of data either side of the mean on a normal distribution curve. As the value of the stranded deviation increased the degree of variation increases

Question 11

if the data overlaps ?

Answer 11

there is no significant difference between data and difference if due to chance

Question 12

what is selection

Answer 12

the process by which organisms that are better adapted to survive and breed. selection is due to the environmental conditions favouring particular phenotypes. organisms with alleles for the selected phenotypes sill haha a greater chance of surviving

Question 13

what is natural selection

Answer 13

when a change in the environment resukts in organisms with a particular phenotype being better adapted these are more likely to survive reproduce and pass on the beneficial allele and the others will die out. there will then be a higher frequency of the allele in the gene pool

Question 14

what are the 3 things adaptations selected for may be:

Answer 14

anatomical- short ears, thicker fur
physiological- kangaroo rats oxidise fat rather to carbs so releases more water in the desert
behavioural- swallows migrate from uk to africa to avoid winter food shortages

Question 15

what is stabilising selection

Answer 15

when the environment is not changing and is stable

Question 16

what is directional selection

Answer 16

occurs when the environment is changing. the change in the environment selects for those organisms with alleles for a phenotype towards the extreme of a range.

Question 17

how does bacteria become resistant to penecillin

Answer 17

results a from a gene mutation which codes for the enzyme penicillinase. This enzyme breaks down penecillin. Bacteria with the resistance will survive and reproduce by binary fission passing the resistance on. This is known as vertical gene transmission.
The presence of the antibiotic leeds to a new environmental condition so frequency of allele increases. The gene for antibiotic resistance is carried on circular loops called plasmids

Question 18

what is genetic diversity

Answer 18

genetic variation in the DNA within a population. members of the same species have different alleles but the same genes. The higher the number of different alleles the greater the genetic diversity. Species that are genetically diverse are better able to adapt to changing environment.

Question 19

What is genetic diversity influenced by

Answer 19

the founder effect
generic bottlenecks
selective breeding

Question 20

What is the founder effect

Answer 20

This occurs when a new population is establish with only a small number of individuals who carry a fraction of the alleles the original population contained. There is then less genetic diversity.

Question 21

What is genetic bottlenecks

Answer 21

A large portion of the population is killed and the few remaining survivors breed to re-establish the population. Generic diversity is restricted and it’s based on individuals with very few alleles.

Question 22

what is selective breeding

Answer 22

breeding together individuals with desired characteristics e.g cows with increased milk production, wheat producing high yields and are disease resistant

Question 23

weaknesses of selective breeding

Answer 23

the effect of inbreeding- leads to a reduction in the variety of alleles therefore reduced genetic diversity. increase the risk of harmful genetic conditions. Whole population could be wiped out by a single pathogen. Unethical. Irreversible

Question 24

positives of selective breeding

Answer 24

more efficient food production
lower prices
improves resistance to disease

Question 25

effect of human activities on species diversity

Answer 25

deforestation- clears out forests with high species diversity that provided a variety of habitats and food sources.
agriculture- large areas of land used to grow crops and use of pesticides and herbicides less habitats less diversity

Question 26

what is courtship and mating behaviour

Answer 26

-recognise members of their own species
-identify a mate who is capable of breeding
-form a pair bong that will lead to successful mating
-synchronise mating

Question 27

how are organisms places into taxonomic groups

Answer 27

based of phylogeny( evolutionary history) and observable features such as homologous structures

Question 28

what are the 3 taxonomic ranks

Answer 28

bacteria
archaea
eukarya

Question 29

what are the taxonomic grouping

Answer 29

Kingdom
Phylum
Class
Order
Family
Genus
Species

Question 30

what’s the memory aid for the classification system

Answer 30

K
P
crisps
on
fire
give
smoke

Question 31

what are the main principles on which the classification system is based

Answer 31

• a hierarchy
  -organisms with similar homologous features
  -phylogenetic groups according the evolutionary history
  -fossil record
  -embryological development
  -biochemical similarities

Question 32

how is dna sequencing tested

Answer 32

DNA hybridisation
DNA sequencing

Question 33

how do we compare proteins

Answer 33

immunological techniques. Antibodies from one species will bind to antigens of another species to form a precipitate.
blood plasma constains a protein called albumin this is infected from species A to species B which will produce antibodies
The antibodies from species B are extracted and mixed with samples of albumin form other species
The antibody binds to complimentary antigens
The greater number of similar antigens, the more precipitate is formed and the more closely related the species are

Question 34

how do we compare proteins

Answer 34

immunological techniques. Antibodies from one species will bind to antigens of another species to form a precipitate.
blood plasma constains a protein called albumin this is infected from species A to species B which will produce antibodies
The antibodies from species B are extracted and mixed with samples of albumin form other species
The antibody binds to complimentary antigens
The greater number of similar antigens, the more precipitate is formed and the more closely related the species are